...convinced of the need for a new constitutional treaty, Prime Minister Mirek Topolanek said on Saturday.
The target date is mentioned in a so-called "Berlin Declaration" to be released at the bloc's 50th anniversary celebration in the German capital on Sunday.
The Czechs had campaigned to avoid any date and any mention in the declaration of reviving the EU's stalled constitution, in limbo since French and Dutch voters rejected it in 2005.
They final wording does not mention the constitution but commits EU leaders to find a "renewed common basis" by 2009, although the Czechs said they would not regard that as a commitment to a new treaty.
"It is apparent that by 2009, when elections for the European Parliament take place, some so far unresolved issues must be resolved," Topolanek said after meeting Danish Prime Minister Anders Fogh Rasmussen.
"We are not making presumptions on whether if it is to be done through a new constitutional treaty, a re-negotiated constitutional treaty or in some other way. However, in this sense, we accept this date for a change of some issues."
The key reforms which most EU states want to salvage from the constitution would give it a long-term president and foreign minister, a simpler decision-making system and more say for the European and national parliaments.
The deadline is significant for the Czechs, because they will hold the EU presidency in the first half of that year.
The ruling right-wing Civic Democrats have been arguing for a different voting system giving small countries more power, and are also uneasy about a common foreign policy.
Topolanek said he viewed the declaration's line on the renewal as a return to the EU's original values and that it was acceptable as such.